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Hi,
I have several collections which are used many times within my application. These collections (which are mainly generic lists) are collections of user-defined objects populated with data from a database, objects instantiated form classes such as regions, ethnicities, disabilities etc.
Is it a good idea to build these collections when the application starts and hold them in memory while the application is running, or would it be better to build them when required then release them when done resulting in many database calls.
Thanks in advance.
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Retaining the lists in memory, I do it all the time. How do you deal with the user adding to the list.
I have a static class MasterTables with a property for each table, in the getter if there is no table I get the data from the database, this requires 1 call.
If the user changes the master table data I simply set the mastertable property to null, next time it is requested a new copy is loaded.
This gets away from the initial hit when starting the app, loading all those master tables can be a noticable delay on the load. I know it can be done in a non ui thread but the master tables style suits me admirably.
Never underestimate the power of human stupidity
RAH
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Ok great, thanks for the tip, sounds like a good idea and one I will definately use 
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One consideration to make, if you edit the data, your local copy is still valid, but if many users use the program and they have a locally stored copy that is different to yours things get out of sync. You can keep a record of when you last loaded the table from the database, and also a record in the database of the last time the data was updated. This will mean you have to check you have the latest version each time, which is a database call, but you will only get the data if it has changed since you last got it.
Only really an issue with a multi user application.
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Ok thanks, good point!
It is a multi-user application, however the lists in question are probably not going to get modified very often. The lists hold data such as ethnicities, regions etc, which are fairly static.
But thanks for pointing that out, something I hadn't considered but will bear in mind in the future 
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While this is what I call a "technical" issue I have not seen it become a problem in a practical sense (I also currently don't work on transactional systems either). I find that master file information is rarely updated once the system is set up and if I enforce a daily restart it pretty much eliminates the problem. I also tells the users it is a potential issues so they are aware of it.
Never underestimate the power of human stupidity
RAH
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Hi,
Any one can tell me. how to import table from sqlserver 2000 data base to sqlserver 2000 database only table,stored procedure and views with out any data.
Thanking for future help
Regards
K. Rajesh Kumar
i am a fresher in software development i have so many doubts in .net so i need to ca
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This question plainly has nothign to do with VB.NET. You can right click and ask SQL Server to generate SQL to recreate the DB. Ideally, you should create a DB by writing scripts which you store in source control and can then run on any DB you like in the future.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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Use a script, you can generate the script from query analyser.
And CG is correct, this belongs in the Database forum.
Never underestimate the power of human stupidity
RAH
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I'm doing an application regarding status of garment production..I use RD ID reader to count each process in garment production. It use USB interface up to 50 device attached in 1 computer. How can I differentiate every 50 input that are coming in almost 1 second?
I know that every USB hardware has unique ID or port that can be used to differentiate their input. But how to implement it in Visual Basic Programming Language?
Thanx b4 for your kind answer
Hermawan
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All the keyboards in Windows show up as a single keyboard. Using all the standard methods, there's no way to tell them apart.
I guess you could use RawInput[^] to figure this out, but now you have the problem of determining which "keyboard" belongs to which scanner.
Seriously, for a project where you deal with this many RFID scanners, I wouldn't be using scanners that show up as keyboard. You can't keep that many scanners within the cabling limits of USB and still have them work properly. I'd be looking at an Ethernet based solution, where each scanner has it's own IP address and can easily be differentiated between multiple devices.
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Hi,
when input devices act like plain keyboards, you can't tell them apart.
And you can't make sure their text strings won't be intertwined.
There areother RFID readers such as this one[^] that have a unique ID, don't emulate keyboards, and come with their own software. That is what you need.
Luc Pattyn [Forum Guidelines] [My Articles]
The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.
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The RFID API's (Symbol based, XR400/450) we use here at work allow the developer to get the antenna number the the tag was scanned at. It will more then likely depend on the API/reader your using.
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What is the name of the API and how to use it?
Thanx
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Hello,
I am trying to write a simple program that will export embedded images from an MS-Word file and save it as an image on my machine (either tiff or jpeg). Is there an image object model built in that can extract this type of data? (Note: the Word file could be open or closed. It does not matter)
Thanks
Harry Wishes
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A while back I wrote an article on XSLT with Word documents, and one of the responders had a great tip on handling embedded images and saving them off:
Word 2003 CodeProject Article Template[^]
XML/XSLT is probably not the first thought you had for a solution on this, but depending on your situation it is a possibility. I think the other route to take is through interop - the Microsoft.Office.Interop.Word namespace.
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I have a small application and use iText to modify a .pdf. I then use the web control to display the pdf in the form for the user.
If the user makes modifications to the paramaters used to generate the document, The application generates a new file, then displays the new file, then attempts to delete the old file; however, I receive a message that the file is still being used by another process. How can I release or dispose of this file, so it may be deleted?
Thanks,
Steve
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What control are you using to show the .PDF file?? You're best source of information liek that would be the people who wrote the control you're using.
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It's the WebBrowser on the Tool bar in Visual Studio. I would assume it is Microsoft that is distributing the object, but I don't know.
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The webbrowser is not showing the PDF. A control registered with Internet Explorer is doing it. The webbrowser control is nothing more than a stripped down version of IE.
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Then I would say it is the Adobe Reader plug-in, as the tool bars present in the frame are the Adobe tools.
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I need help downloading only the new files from an FTP server. There are more than 30,000 files in a table and I only need the most recent files. The files are by date and time. Any help would be great! Thanks.
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So what's the problem?? You're going to have to get the entire list of files, keep track of what files are there. The next time you get the list, compare the new list to the old one. You've got your list of new files to download then. Download them, keep track of which ones you've successfully downloaded. Once you get the files downloaded, you've got your new list of files you have.
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Hi,
I need to write a script(using vbscript) to send a XML content to the X-mailbox. My mailbox has been configured in Lotus notes. I'm currently using the script like below, but here while sending a mail I want to set the mailcontent type as 'Text\plain' or 'MIME message' type. I should not send a mail which is in Richtext format.
Please can anyone help me to find the solution for this?
function sendemail(emplnum,msg,subject)
dim objNotesSession, objNotesDoc, objNotesDb, objNotesBody
Set objNotesSession = createobject("Notes.NotesSession")
If objNotesSession is Nothing then
msgbox "Could Not create a Session of Notes", 16, "Notes Session Error."
end if
'call objNotesSession.Initializeusingnotesusername("IT-TeknionMalaysia","coffeetime99")
set objNotesDB = objNotesSession.GETDATABASE("TFSMDMS1","mail\slim.nsf")
'Create the mail document
set objNotesDoc = objNotesDB.CREATEDOCUMENT
'set objNotesDoc.ReplaceItemValue("Form", "Memo")
set objNotesBody = objNotesDoc.CreateRichTextItem("BODY")
set curEmployee = new Employee
'Response.Write "employeenum:" & emplnum
curEmployee.GetEmployeeInfo(emplnum)
if curEmployee.err = "" then
With objNotesDoc
.Form = "Memo"
.subject = subject
.Sendto = "seokbee.lim@teknion.com"
.body = msg
.postdate = Date
End With
if true then 'true for real email, false if testing
if objnotesdoc.send = false then
Response.write "The email could not be sent, " & _
"please notify your employee on the status of his/her leave application.<BR>"
response.write emailmsg.log
else
Response.write "<center>An email has been sent to notify " & curEmployee.Name & " of the leave application.</center><br>"
end if
else
'response.write("To: " & curEmployee.Name & " <" & curEmployee.Email & ">" & "<BR>")
'response.write("From: " & emailmsg.From & "<BR>" )
'Response.Write("Subject: " & emailmsg.Subject & "<BR>")
'Response.Write("Body: <BR>" & emailmsg.HTMLBody & "<BR>")
end if
else
Response.write(curEmployee.err)
Response.End
end if
end function
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